Photocatalytic Active Sites Research Articles

Interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with metallic Fe/Al[sbnd]N bonds for efficient photocatalytic degradation of tetracycline hydrochloride

To improve the photogenerated electron–hole separation efficiency and the number of reactive oxygen species of g-C3N4 in visible light. Herein, an interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with Fe/AlN bonds were prepared, which shows highly enhanced photocatalytic degradation performance with excellent structural stability. The interfacial structure of g-C3N4 was precisely regulated by metal Fe/Al on the surface of layered double hydroxides (LDHs), which could form Fe/AlN bonds as the interfacial charge transfer channels. In addition, the metal Ni and Fe/Al on the surface of LDHs nanosheets can furnish more photocatalytic active sites and interface synergy. The obtained 7 %NiFe-LDHs/g-C3N4 owns the degradation rate of 99.23 % for tetracycline hydrochloride (TCH) in visible light. This work highlights a rational interface engineering strategy for the formation of a composite structure with interface interaction for efficient photocatalysts.

Ultra-fine carbon decorated TiO2/C/g-C3N4 hybrid for strong physical adsorption and efficient photodegradation of pollutants

Enhancement in the visible light absorption and efficient interfacial charge transfer is crucial for optimizing photocatalytic efficiency in the degradation of pollutants such as methyl orange (MO) and formaldehyde. This study focuses on the properties of a TiO2/C/g-C3N4 hybrid efficient photocatalyst is developed by employing an air calcination method to deposit graphitic nitride (g-C3N4) onto a carbon-modified TiO2 surface. The characterization techniques, including high-resolution transmission electron Microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), were used to provide a comprehensive understanding of the material’s structural, morphological, thermal, and chemical properties. This hybrid catalyst is specifically engineered for the efficient decomposition of methyl orange (MO) and formaldehyde, demonstrating a significant increase in photocatalytic activity. The TiO2/C/g-C3N4 photocatalyst also exhibits an enhanced specific surface area of 181.2 m2/g, which facilitates increased physical adsorption and photo-catalytic active sites. Experimental results confirm that this catalyst effectively adsorbs MO physically even in the dark without degradation. Combining physical and photo-catalytic functions, this catalyst degrades 94 % of MO within 180 min with the initial concentration 0.2 mol/L of MO, and achieves almost 100 % decolorization of MO under visible light irradiation. Notably, the catalyst retains its high activity after 4 cycles of MO degradation, underscoring its durability and consistent performance. Additionally, the hybrid catalyst features a staggered type-II energy level configuration, which effectively enhances charge separation and boosts photocatalytic efficacy. The incorporation of an ultrafine carbon layer further augments electron mobility towards the surface, crucial for effective catalytic reactions. This study paves the way for future development of highly efficient photocatalytic materials for environmental purification.

Enhanced hydrogen evolution performance of twinned Mn0.65Cd0.35S with Zn-doped cadmium selenide under visible light irradiation

The cadmium manganese sulfide, despite being recognized as a highly efficient photocatalytic semiconductor for hydrogen evolution, faces significant challenges in terms of charge recombination when used solely as a catalyst for photocatalytic hydrogen production. The construction of heterojunction photocatalysts is regarded as one of the effective strategies to enhance the efficiency of photocatalytic hydrogen production. In this work, Zn-doped CdSe was adopted to enhance the photocatalytic active sites of the twinned Mn0.65Cd0.35S. As results, the photocatalytic hydrogen evolution of Zn–CdSe-1/T-MCS-40 can reach approximately 47447.15 μmol g−1 after 5 h, representing a 15 times increase compared to Mn0.65Cd0.35S. Besides, the hydrogen evolution rate shows almost no significant attenuation after four consecutive cycles (20 h). The significant achievement can be largely attributed to the successful construction of an S-scheme heterojunction of Zn–CdSe-1/T-MCS-40, which effectively minimized the charge transfer distance and suppressed the recombination of photo-generated electron-hole pairs. Additionally, the incorporation of Zn-doped CdSe significantly expands the response range to visible light, thereby providing a conceptual framework for advancing the design of solar-to-chemical energy conversion and effectively guiding the fabrication of metal sulfide-based photocatalytic heterojunctions.

Plasmonic Au-MoS2 Nanohybrids Using Pulsed Laser-Induced Photolysis Synthesis for Enhanced Visible-Light Photocatalytic Dye Degradation.

The Au-MoS2 nanocomposites (NCPs) exhibit excellent visible-light photocatalytic activity and potential applications in the photocatalytic degradation of organic dyes. In this study, an Au-MoS2 heterojunction structure with Au nanoparticles (NPs) deposited on MoS2 nanosheets was synthesized via the pulsed laser-induced photolysis method. The influence of Au content on the photocatalytic performance was systematically investigated, and the working mechanism under visible light excitation was elucidated. The optimal Au-MoS2 NCPs exhibited efficient degradation of methylene blue (MB) dye, mainly attributed to the plasmon resonance effect of Au NPs which facilitated the visible light harvesting and hot electron injection. The Au/MoS2 interface promoted the separation and transfer of photogenerated charge carriers. The electrostatic adsorption between positively charged MB molecules and the negatively charged MoS2 surface favored the affinity toward active sites. Furthermore, the photogenerated electrons and holes participated in generating reactive oxygen species such as superoxide and hydroxyl radicals, which initiated the oxidative degradation of MB. The PLIP-introduced Au NPs not only endowed the material with excellent visible light responsivity but also possibly modulated the electronic structure and photocatalytic active sites of MoS2 through an intrinsic effect, providing new insights for further enhancing the photocatalytic performance of Au-MoS2 NCPs.

Visible light photocatalytic degradation of oxytetracycline hydrochloride using chitosan-loaded Z-scheme heterostructured material BiOCOOH/O-gC3N4

In this work, a Z-scheme heterostructured BiOCOOH/O-gC3N4 material was synthesized and immobilized on chitosan (CTS) to obtain the BiOCOOH/O-gC3N4/CTS photocatalytic material for photocatalytic degradation of oxytetracycline hydrochloride (CTC).Our findings indicate that the composite material BiOCOOH/O-gC3N4, as well as the BiOCOOH/O-gC3N4/CTS composite membrane, displayed a significantly higher efficiency in photocatalytic degradation of CTC compared to BiOCOOH alone, owing to the synergistic effect of adsorption and photocatalysis. Following four cycles of use, the composite material retained around 96 % of its initial photocatalytic degradation activity. The addition of CTS in the photocatalytic material resolved issues such as aggregation and difficult recovery commonly encountered with powder materials, thereby facilitating effective collision between the photocatalytic active sites and CTC. Experimental and theoretical calculations provided confirmation that the combination of BiOCOOH and O-gC3N4 effectively enhanced the light absorption capacity and photocatalytic performance. Furthermore, we investigated the influence of environmental factors such as pH value and anions on the photocatalytic degradation experiment, which offers valuable insights for the application of composite catalysts in wastewater treatment.

Quenching-induced oxygen vacancy engineering boosts photocatalytic activities of CaTiO3

Oxygen vacancies (VOs) play a pivotal role in promoting the photocatalytic activities of perovskite oxides. Herein, we proposed a simple and effective strategy of introducing both surface oxygen vacancies and bulk single electron trapped oxygen vacancies (SETOVs) into CaTiO3 by ethanol quenching. The purchased CaTiO3 was preheated at 800 °C and then the hot CaTiO3 was quenched in ethanol instantly. The ethanol-quenched QE-CaTiO3 delivers much improved photocatalytic activities towards both RhB degradation and hydrogen evolution under visible light irradiation by 6.5 and 65.2 times, respectively, in comparison with the pristine CaTiO3. Both the bulk SETOVs and surface VOs enhance light absorption, and the surface VOs serve as photocatalytic active sites. DFT calculations further reveal the narrowed band gap and accumulated charge density near the Fermi level in QE-CaTiO3, which help the visible light absorption, facilitate charge carriers generation and migration, and promote photocatalytic activities. Our findings provide an efficient and easily scalable approach to engineering oxygen vacancy defects in photocatalysts and other catalysts.

Frustrated Lewis pairs created by Ce-doped Bi2MoO6: A universal strategy to promote efficient utilization of H2O2 for Fenton-like photodegradation

Photo-Fenton-like technology based on H2O2 is considered as an ideal strategy to generate reactive oxygen species (ROS) for antibiotic degradation, but O2 overflow in the process severely limits the utilization efficiency of H2O2. Herein, we fabricate Bi2MoO6 (BMO) photocatalyst modified with Frustrated Lewis pairs (FLPs) as a Fenton catalyst model for enhancing reuse of spilled O2. The FLPs created by the introduction of cerium and oxygen vacancy were found to contribute to regulate the electronic structure of BMO and further improve the acidic and basic properties of photocatalyst surface. More importantly, the frustrated acid and base sites can enhance the H2O2 and O2 interfacial adsorption process and provide an Ce4+-Ov-O2− active site on the surface of Ce-BMO nanosheets, which can promote O2/•O2−/1O2/H2O2 redox cycles to achieve high H2O2 utilization efficiency. Specifically, in the experiment using tetracycline as a photocatalytic degradation object, the degradation activity of Ce-BMO was 2.15 times higher than that of BMO pure phase. Quenching experiments and EPR assays also confirmed that 1O2 and •O2− were the dominant oxidative species. This study systematically reveals the design of Fenton photocatalytic active sites at the atomic scale and provides new insights into constructing FLPs photocatalysts with high H2O2 utilization efficiency.

Homogenization spin coating strategy for synthesizing IM-BTO photocatalytic membrane aims to tetracycline selectively degradation

Photocatalytic membrane technology is a promising technology for advanced water treatment. However, as a simple, fast, and stable spin coating method for photocatalytic membrane preparation, the spin coating solution often used in spin coating can cause the pore plugging on the membrane surface and encapsulates photocatalysts, which seriously affects the flux of the membrane and the exposure of the photocatalytic active site. Here, this work adopted a homogenization spin coating strategy, using polyvinylidene difluoride (PVDF) solution as the spin coating solution to prepare the highly exposed imprinted bismuth titanate porous photocatalytic membrane (IM-BTOM). Due to the same composition of PVDF solution as the PVDF substrate membrane, IM-BTOM basically retained the good porous structure of the membrane. The homogenization spin coating strategy not only endowed IM-BTOM with high flux (4545.45 L m-2h−1 bar−1), but also prevented the encapsulation of IM-BTO powder materials, fully exposing the photocatalytic active sites, thereby obtaining better photocatalytic ability and selectivity. The degradation rate of tetracycline with IM-BTOM was nearly three times that with the conventional cellulose acetate spin coating membrane. Meanwhile, the existence of imprinting cavities also endowed IM-BTOM with high selectivity for the target pollutant, with a selectivity coefficient of up to 2.66. This work provides a new idea for preparing high-efficient photocatalytic membrane by spin coating.

The Cd0.8Zn0.2S/In2S3 porous nanotubes heterojunction towards enhanced visible light photocatalytic H2 evolution and photodegradation via MOFs self-template and bimetallic synergism

The Cd0.8Zn0.2S/In2S3 porous nanotubes heterojunction is fabricated via chemical-hydrothermal method. Cd0.8Zn0.2S/In2S3 heterojunction (Cd0.8Zn0.2S/In2S3-3) exhibits a prominent enhanced photocatalytic HER activity (∼3480.91 μmol g−1 h−1, AQE of ∼12.09%) and photodegradation than single In2S3 (∼40 folds/∼10 folds) and single Cd0.8Zn0.2S (∼30 folds/∼4 folds). There, the Cd0.8Zn0.2S/In2S3 heterojunction with great potential gradient, bimetallic synergism, crystal lattice matching and visible light response can ameliorate carrier efficiency effectively, including transportation increasing, lifetime prolonging, recombination decreasing, and can be supported by the DFT. In addition, formed porous nanotubes microstructural can increase photocatalytic active sites and light reflections, and shorten carrier pathway, meanwhile maintaining a good stability. Herein, the modification of heterojunction, bimetallic synergy and hollow tubular structure can provide new sights for preparing green energy-environmental materials.

Fe-doped g-C3N4 with duel active sites for ultrafast degradation of organic pollutants via visible-light-driven photo-Fenton reaction: Insight into the performance, kinetics, and mechanism

The photo-Fenton process provides a sustainable and cost-effective strategy for removing refractory organic contaminants in wastewater. Herein, a high-efficient Fe-doped g-C3N4 photocatalyst (Fe@CN10) with a unique 3D porous mesh structure was prepared by one-pot thermal polymerization for ultrafast degradation of azo dyes, antibiotics, and phenolic acids in heterogeneous photo-Fenton systems under visible light irradiation. Fe@CN10 exhibited a synergy between adsorption-degradation processes due to the co-existence of Fe3C and Fe3N active sites. Specifically, Fe3C acted as an adsorption site for pollutant and H2O2 molecules, while Fe3N acted as a photocatalytic active site for the high-efficient degradation of MO. Resultingly, Fe@CN10 showed a photocatalytic degradation rate of MO up to 140.32 mg/L min−1. The dominant ROS contributed to the removal of MO in the photo-Fenton pathway was hydroxyl radical (•OH). Surprisingly, as the key reactive species, singlet oxygen (1O2) generated from superoxide radical (•O2−) also efficiently attacked MO in a photo-self-Fenton pathway. Additionally, sponge/Fe@CN10 was prepared and filled in the continuous flow reactors for nearly 100% degradation of MO over 150 h when treating artificial organic wastewater. This work provided a facile route to prepare highly-active Fe-doped photocatalysts and develop a green photocatalytic system for wastewater treatment in the future.

Top-down synthesis of high-performance lead-free double layer perovskite Cs4CuSb2Cl12 with large specific surface area and rich defects for efficient photocatalytic CO2 reduction

In recent years, there has been significant progress in the field of perovskite research. One area that has garnered attention is lead-free perovskite due to its stability, lack of toxicity, and exceptional optical properties. In this study, we successfully synthesized environmentally friendly, small-sized double-layer perovskites Cs4CuSb2Cl12 using a top-down method involving ball milling. The resulting Cs4CuSb2Cl12 nanoparticles exhibit high photocatalytic capacity, with a 1.60-fold increase in CO yield under full spectrum irradiation for 4 h, from 45.01 μmol/g to 72.17 μmol/g compared to the original material. Additionally, CO evolution under NIR light illumination for 4 h increased from 2.31 μmol/g to 5.37 μmol/g. The top-down treatment resulted in smaller particle size and larger specific surface area, shortened carrier transmission distance, and enhanced electron concentration. Furthermore, the material’s surface presented a high concentration of defects, displayed high absorption capability across the entire spectrum, and abundant photocatalytic active sites. This study introduces an effective and environmentally-friendly strategy to enhance the photocatalytic efficiency of Cs4CuSb2Cl12, providing a new perspective for providing the photocatalytic capability of these materials.

Mesostructured Nonwovens with Supramolecular Tricycloquinazoline Nanofibers as Heterogenous Photocatalyst

Functional supramolecular nanostructures are a promising class of materials, which can be used as potential heterogeneous photocatalysts in water. Self‐assembly to nanoobjects in solution typically requires large solubilizing groups linked to the photoactive building block, and possibly hampers access to the photocatalytic active sites. Herein, a straightforward method to fabricate supramolecular nanofibers based on the disclike tricycloquinazoline (TCQ) by physical vapor deposition (PVD) is reported. It is demonstrated that TCQ can be assembled on different substrates into supramolecular nanofibers with diameters of about 70 nm resulting in densely packed fiber layers. With optimized conditions, the evaporation time allows full control over the fiber length and the absorbance of the TCQ fiber layer. A bottlebrush‐like morphology with TCQ nanofibers is realized using glass‐microfiber nonwovens as porous support. These mesostructured nonwovens can be used as photocatalysts for the degradation of rhodamine B in a batch process in water where the morphology remains intact after the reaction. After photocatalytic degradation of rhodamine B or tetracycline under continuous flow conditions, the supramolecular TCQ nanofibers still remain on the support. These findings demonstrate that PVD is a feasible approach to achieve functional mesostructured nonwovens with controlled morphology for use and reuse in catalytic applications.

Fine-tuning metal nodes accessibility of metal-organic frameworks for boosting net photocatalytic H2O2 production

Coordination unsaturated metal nodes in metal-organic frameworks (MOFs) work as photocatalytic active sites in H2O2 production, but over-exposed metal nodes also act as decomposing sites towards the photogenerated H2O2, resulting in low net yield. Herein, fine-tuning of metal nodes accessibility in MOFs was applied for boosting net photocatalytic H2O2 production. The accessibility of the nodes was fine-tuning through varying the feeding amount of benzoic acid (BA) during synthesis, treated MOFs with HCl, re-installed with variable BA, etc. The correlation between nodes accessibility and H2O2 production was systematically investigated, which demonstrates that the NH2-UiO-66-XBA with higher compensated BA possessing large steric effect at nodes would hinder the decomposition of photogenerated H2O2, thus promoting the net H2O2 yield. As a contrary, NH2-UiO-66-HCl without BA showed a distinctive decomposition rate of H2O2, resulting in a low net H2O2 production yield. The re-installed NH2-UiO-66-ReBA10 with compensated BA showed a recovered H2O2 production yield. A combination of O2 sorption isothermals, PL spectra, ESR spin-trap plots, and Koutecky-Levich plots disclosed that O2 was enriched by the framework and then reduced at the metal nodes mainly through two-electron pathway, especially for highly compensated MOFs. This strategy had been applied to other MOFs for boosting the H2O2 production like NU-1401 and PCN-222. This work reveals the fine-tuning of metal nodes accessibility in MOFs is an effective way for boosting H2O2 production.

Fabrication of Bi/BiOCOOH/PVDF with improved photocatalytic activity for the degradation of ciprofloxacin

The development of a low-cost and recyclable method for wastewater treatment has been a major challenge. Polyvinylidene fluoride (PVDF) membranes have received considerable attention owing to their excellent mechanical strength, unique antioxidant properties, and low cost. In this study, Bi/BiOCOOH/PVDF composite membrane materials were prepared using a simple two-step solvent thermal method and phase conversion method. The results showed that under the synergistic action of adsorption and photocatalysis, the photocatalytic degradation efficiency of Bi/BiOCOOH composite material and Bi/BiOCOOH/PVDF composite membrane material for ciprofloxacin (CIP) was much higher than that of BiOCOOH. The introduction of PVDF acted as a carrier, improved the adsorption of the catalytic material to CIP, and facilitated the effective collision of the photocatalytic active site and CIP. The experimental results and theoretical calculations confirmed that the combination of Bi and BiOCOOH effectively improved the light absorption capacity and photocatalytic performance. The reproducibility test revealed that the small amount of new composite catalyst for Bi/BiOCOOH/PVDF as a carrier was lost and that the Bi/BiOCOOH/PVDF catalyst still had high catalytic activity. In addition, the influence of water matrix factors, such as pH and anion, on the photocatalytic degradation experiment was investigated, which would provide some reference for the actual wastewater treatment of the composite catalyst. This study demonstrates a photocatalytic activation mechanism between metals and semiconductors and provides some basis for constructing catalysts for the synergistic and effective treatment of water pollution through a combined adsorption and photocatalysis process.

Oxygen-tolerant and recyclable graphitic carbon nitride (g-C3N4) catalyzed photo-induced electron/energy transfer reversible addition-fragmentation chain transfer polymerization (PET-RAFT) without any additives

The existing photo-induced electron/energy transfer reversible addition-fragmentation chain transfer polymerization (PET-RAFT) systems using g-C3N4 as catalyst are complicated and often require modification of g-C3N4 or additives as co-catalyst. Herein, we propose an economical g-C3N4 catalyzed PET-RAFT polymerization without any additives. The good catalytic ability of g-C3N4 is attributed to the fact that the thermal exfoliation by secondary calcination increases the specific surface area and thus exposes more photocatalytic active sites. The g-C3N4 catalyzed PET-RAFT polymerizations of methyl methacrylate were successfully carried out under blue LEDs. The faster polymerization rates without prior deoxygenation showed good oxygen-tolerant. The g-C3N4 can be easily recovered after polymerization and cycled at least seven times with little loss of catalytic performance.

Dispersible Supertetrahedral Chalcogenide T3 Clusters: Photocatalytic Activity and Photogenerated Carrier Dynamics

Herein, we synthesized two isostructural supertetrahedral T3 cluster-based chalcogenide compounds by an ionic liquid-assisted precursor technique, namely [Bmmim]6In10Q16Cl4∙(MIm)4 (Q = S (In-S), Q = Se (In-Se), Bmmim = 1-butyl-2,3-dimethylimidazolium, MIm = 1- methylimidazole). The two compounds consist of a pure inorganic discrete supertetrahedral [In10Q16Cl4]6- T3 cluster and six charge-balancing [Bmmim]+ anions. The T3 clusters could be highly dispersed in dimethyl sulfoxide (DMSO), exposing more photocatalytic active sites, which makes the highly-dispersed In-Se cluster exhibit ~5 times higher photocatalytic H2 evolution activity than that of the solid-state under visible light irradiation. Comparatively, the photocatalytic performance of the highly-dispersed In-S cluster is only slightly higher than that of the solid state, as its inferior visible-light absorption capability limits the effective utilization of photons. More importantly, through tracking the photogenerated carriers dynamics of highly-dispersed T3 clusters by ultrafast transient absorption (TA) spectroscopy, we found that the photogenerated electrons in the In-S cluster would suffer a rapid internal deactivation process under illumination, whereas the photoexcited electrons in the In-Se cluster can be captured by its surface active centers that would effectively reduce its photogenerated carrier recombination, contributing to the significantly enhanced photocatalytic activity. This work enriches the species of highly-dispersed metal-chalcogenide nanoclusters and firstly investigates the relationship between the structures and photocatalytic performances of nanoclusters by ultrafast excited-state dynamics, which is expected to promote the development of atomically precise nano-chemistry.

Kinetically and Thermodynamically Favorable Ni–Al Layered Double Hydroxide/Ni-Doped Zn0.5Cd0.5S S-Scheme Heterojunction Triggering Photocatalytic H2 Evolution

Layered double hydroxide (LDH)-based photocatalysts have attracted more attention in photocatalysis due to their low cost, wide band gaps, and adjustable photocatalytic active sites; however, their low photogenerated carrier separation efficiency limits their photocatalytic efficiency. Herein, a NiAl-LDH/Ni-doped Zn0.5Cd0.5S (LDH/Ni-ZCS) S-scheme heterojunction is rationally designed and constructed from kinetically and thermodynamically favorable angles. The 15% LDH/1% Ni-ZCS displays comparable photocatalytic hydrogen evolution (PHE) activity with a rate of 6584.0 μmol g-1 h-1, which exceeds by ∼6.14- and ∼1.73-fold those of ZCS and 1% Ni-ZCS, respectively, and outperforms most of the previously reported LDH-based and metal sulfide-based photocatalysts. In addition, the apparent quantum yield of 15% LDH/1% Ni-ZCS reaches 12.1% at 420 nm. In situ X-ray photoelectron spectroscopy, photodeposition, and theoretical calculation reveal the specific transfer path of photogenerated carriers. On this basis, we propose the possible photocatalytic mechanism. The fabrication of the S-scheme heterojunction not only accelerates the separation of photogenerated carriers but also decreases the activation energy of H2 evolution and improves the redox capacity. Moreover, there are huge amounts of hydroxyl groups distributed on the surface of photocatalysts, which is highly polar and easy to combine with H2O with a large dielectric constant to form a hydrogen bond, which can further accelerate PHE.

Cation exchange synthesis of hollow-structured cadmium sulfide for efficient visible-light-driven photocatalytic hydrogen evolution

Efficient solar absorption and photoinduced charge separation are extremely important for solar-energy conversion on semiconductor photocatalysts. To advance the photocatalytic performance, we developed a general templated-assisted reverse cation exchange strategy to successfully synthesize hollow-structured CdS semiconductors with the textile structural surface. The crystal phase, particle morphology, optical/electrical properties, and photocatalytic performance of the as-syntheszied sample are investiagted by XRD, SEM, TEM, XPS, DSR, PL, ESR photoelectrochemical measurements, and Photocatalytic H2 evolution test. The final CdS sample exhibits an enhanced photocatalytic hydrogen evolution rate of up to 965 μmol·g−1 h−1, 2.8 times higher than the reported CdS nanorods. Based on the experimental and characterization results, the improved photocatalytic activity of the cadmium sulfide semiconductor can be ascribed to the special hollow cubic structure with a thin shell, which can enhance the light-harvesting ability and provide abundant photocatalytic active sites for facilitating the separation of photogenerated electron/hole pairs. This synthetic strategy may pave a new path for the rational design of efficient sulfur-based semiconductor photocatalysts for solar driven H2 production.

G‐C3N4 Monolayer/2D Mica Nanohybrids with Highly Effective UV–HEV‐Screening Function

AbstractExcessive exposure to ultraviolet (UV) and high‐energy visible (HEV) light can cause sunburns, wrinkles, and even skin cancer. Therefore, the development of effective UV–HEV‐shielding agents is of great importance to human health. In this study, semiconducting graphitic carbon nitride (g‐C3N4) is incorporated into the interlayer space of mica through the intercalation of cyanamide and subsequent pyrolysis reactions to form a semiconductor–insulator nanohybrid, namely g‐C3N4–mica, with a 1:1 heterostructure. The g‐C3N4–mica nanohybrid exhibits excellent UV–HEV absorption properties below 450 nm, and its photocatalytic activity is quenched owing to the effective screening of photocatalytic active sites by the insulating mica. It is strongly believed that the proposed g‐C3N4–mica nanohybrid can be applied as a UV–HEV blocking agent owing to its excellent UV–HEV (200–450 nm)‐screening property without any photocatalytic effect or phototoxicity.

Tuning excited state electronic structure and charge transport in covalent organic frameworks for enhanced photocatalytic performance

Covalent organic frameworks (COFs) represent an emerging class of organic photocatalysts. However, their complicated structures lead to indeterminacy about photocatalytic active sites and reaction mechanisms. Herein, we use reticular chemistry to construct a family of isoreticular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local pore characteristics of the COFs modulated using different linkers. The excited state electronic distribution and transport pathways in the COFs are probed using a host of experimental methods and theoretical calculations at a molecular level. One of our developed COFs (denoted as COF-4) exhibits a remarkable excited state electron utilization efficiency and charge transfer properties, achieving a record-high photocatalytic uranium extraction performance of ~6.84 mg/g/day in natural seawater among all techniques reported so far. This study brings a new understanding about the operation of COF-based photocatalysts, guiding the design of improved COF photocatalysts for many applications.